Gosain A K, Amarante M T, Hyde J S, Yousif N J
Department of Plastic and Reconstructive Surgery, Medical College of Wisconsin, Milwaukee, USA.
Plast Reconstr Surg. 1996 Sep;98(4):622-36. doi: 10.1097/00006534-199609001-00005.
An anatomic study was performed on living subjects using magnetic resonance imaging (MRI) to distinguish the relative contribution of skin, subcutaneous tissue, and muscle to dynamic changes in the nasolabial fold during facial animation and aging. MRI scans with the face in repose and then holding a full smile were performed in both young and old adult subjects. Anatomic landmarks were identified, and measurements characterizing their position were made on the MRI console. MRI resulted in excellent image resolution of facial tissue planes. Comparison between young and old subjects with the face in repose demonstrated that progressive thickening of the dependent portion of the check fat pad and overlying skin, with no appreciable change in the muscle plane comprising the levators of the upper lip, resulted in a deeper and more acute nasolabial fold in older subjects. In both age groups there was significant shortening of the mimetic muscles with smiling, with the lateral mimetic muscles drawn closer to the underlying facial bones. This was accompanied by redistribution of the cheek fat pad, thereby maintaining projection of surface landmarks within the cheek mass in young subjects with smiling. These findings indicate that in order to diminish the nasolabial fold, surgery for facial rejuvenation should be directed to the skin and subcutaneous tissue planes superficial to the mimetic muscles to the upper lip. In order to recreate a natural nasolabial fold during surgery for facial reanimation, contraction of the levator muscles to the upper lip should result in redistribution of the cheek fat pad without change in surface projection of the cheek mass or upper lip; this can only be accomplished if the reconstructed levator muscle is positioned deep to the cheek fat pad, with its insertion toward the deep (mucosal) surface of the upper lip.
利用磁共振成像（MRI）对活体受试者进行了一项解剖学研究，以区分在面部表情活动和衰老过程中，皮肤、皮下组织和肌肉对鼻唇沟动态变化的相对贡献。对年轻和老年成年受试者进行了面部静止及保持全笑状态下的MRI扫描。确定了解剖标志，并在MRI控制台对其位置进行测量。MRI获得了面部组织层面的高分辨率图像。面部静止状态下年轻与老年受试者的比较显示，颊脂垫下垂部分及上方皮肤逐渐增厚，而上唇提肌所在的肌肉层面无明显变化，这导致老年受试者的鼻唇沟更深、更明显。在两个年龄组中，微笑时表情肌均显著缩短，外侧表情肌向下方面部骨骼靠近。这伴随着颊脂垫的重新分布，从而在微笑的年轻受试者中保持了颊部表面标志的投影。这些发现表明，为了减轻鼻唇沟，面部年轻化手术应针对上唇表情肌表面的皮肤和皮下组织层面。为了在面部重建手术中重现自然的鼻唇沟，上唇提肌收缩应导致颊脂垫重新分布，而颊部或上唇的表面投影无变化；只有当重建的提肌位于颊脂垫深部，且其附着点朝向唇的深部（黏膜）表面时，才能实现这一点。
